Hair that has been thoroughly cleansed, but not conditioned, is extremely difficult to comb, in either the wet or dry state, because the individual hair fibers tend to snarl, kink, and interlock with each other. Incompletely dried hair, such as towel dried hair, has poor brushing properties, then, even after complete drying, the combing and brushing properties of the hair remains poor. Often, the hair also has undesirable electrostatic properties in a low humidity atmosphere that causes the hair to "fly away", thereby further reducing the esthetic properties of the hair. In addition, normal hair can be so fine, limp and lacking in body that the hair does not hold a hair set well. Also, the hair can lose body and can be weakened further by being subjected to chemically-active hair treatments such as permanent waves and tints. The hair can be weakened even further by other contributing factors, such as bleaching by sun exposure or chlorinated swimming pool water, wind, pollution, and the like.
Normal hair is usually hydrophobic. However, many hair-treating compositions remove the natural hydrophobic components from the hair. As a result, the hydrophobicity of the hair decreases, the relative porosity of the hair increases and the hair tends to absorb water and swell more readily. In such a weakened and porous state, the water-swollen hair is more vulnerable to stretching and breaking. Therefore, investigators have sought to counteract the unmanageability of thoroughly cleansed hair by utilizing compositions containing various conditioning compounds. When applied to the hair, these compositions demonstrated varying abilities to improve the manageability and the physical and esthetic properties of the hair.
Accordingly, investigators have found compositions and formulation techniques to provide a hair-treating product that imparts beneficial hair conditioning properties such as improved manageability, easy application and combing, quick drying and non-stickiness, good hair body and bounce, increased hair volume and gloss, and hydrophobicity. It is evident that in the formulation of any end-use product, some of these benefits are sacrificed to some degree to achieve a competing benefit. Therefore, the formulation of hair conditioning products has proved difficult. As a result, hair conditioning products have been developed in a variety of product forms. For example, hair conditioning products are available as gels, aerosol foams, all-purpose lotions, hair sprays, holding lotions, conditioners and shampoos. However, in using presently available commercial products, consumers must sacrifice certain desirable physical or esthetic hair properties in order to achieve or improve other desirable physical or esthetic properties.
Consequently, the present invention relates to a composition and method of treating the hair that improve the physical and esthetic properties of the treated hair. It has been found that by treating the hair with a microemulsion composition including a water-insoluble amino-containing compound; an ionizable metal salt, wherein the metal has a valence of at least II; an ester compound of the general structural formula: EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2 ;
and water, the physical and esthetic properties of the hair are improved, such that the hair demonstrates durable conditioning properties such as wet and dry combing, body and manageability. Thus, the improved physical and esthetic properties imparted to the hair upon treatment with a composition of the present invention obviates the need to treat the hair each day or after each shampooing.
Therefore, the present invention is directed to a hair-treating composition, in the form of a stable, translucent or transparent microemulsion that has demonstrated an improved ability to deposit conditioning agents onto the hair, and an improved durability of conditioning agents deposited on the hair; has improved the wet and dry combing of treated hair; and has imparted satisfactory, and durable, esthetic and physical properties to freshly-cleaned and dried hair, including, in particular, combing, manageability, body and shine. The microemulsion compositions of the present invention are exceptionally stable and can be formulated into a variety of hair care products, including conditioning shampoos, conditioners, mousses, fixatives, lotions, hair sprays, gels, and similar hair-treating and hair-styling products.
In general, emulsions are classified as macroemulsions or as microemulsions depending upon the droplet size of the liquid present in the internal, or dispersed, phase of the emulsion. Macroemulsions, having droplets with an average diameter of from about 10 microns to about 1000 microns, do not permit light to pass through the emulsion. Therefore, macroemulsions typically appear milky white. Microemulsions, however, are stable compositions including internal phase droplets that are significantly smaller than the droplets in the internal phase of macroemulsions, and having an approximate average diameter of less than about 150 nm. Microemulsions are generally more stable than macroemulsions, and typically are translucent, and often transparent, in nature.
Emulsions also are classified further depending on the nature of the liquid forming the internal, or dispersed, phase and the nature of the liquid forming the external, or continuous, phase. An emulsion wherein a water-insoluble compound, like an oil, is dispersed as droplets throughout a continuous aqueous phase is termed an oil-in-water emulsion. However, if water is the dispersed phase and an oil is the continuous phase, the emulsion is termed a water-in-oil emulsion. Whether the aqueous phase or the oil phase is the dispersed phase or the continuous phase depends primarily on the emulsifying agent, or agents, used, and the relative amounts of the two liquid phases. The microemulsions of the present invention preferably are oil-in-water microemulsions, wherein the continuous phase is water. However, water-in-oil microemulsion compositions also are useful in the method of the present invention.
Accordingly, the present invention relates to a microemulsion composition and method of treating the hair that improve the physical and esthetic properties of the treated hair. It has been found that by treating the hair with a microemulsion composition including a water-insoluble amino-containing compound, such as an amine or an amino-functionalized silicone compound, like trimethylsilylamodimethicone; an ester compound having the general structural formula: EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2,
like isopropyl C.sub.12-15 pareth-9-carboxylate; an ionizable metal salt, wherein the metal has a valence of at least II, like magnesium chloride; and water, the physical and esthetic properties of the treated hair are improved such that the hair is conditioned and demonstrates durable conditioning properties.
Various effects resulting from treating human hair with metal salts or amines are known. For example, polyvalent metal salts are known in the art for their astringent and antiperspirant effects on skin. Hewitt et al., in U.S. Pat. No. 3,842,847, taught the use of astringent water-soluble salts of aluminum, hafnium, zirconium, zinc and like metals in a shampoo and hair treatment to diminish scalp perspiration. Hewitt et al. also reported antistatic and anti-soiling effects on hair treated with aqueous rinses including aluminum chlorohydrate. Hewitt et al. theorized that the astringent metal salt reacted with the hair keratin to reduce the anionic nature of the hair, and therefore, to reduce "fly-away" hair. However, to obtain the benefits disclosed by Hewitt et al., the hair had to be water rinsed after treatment until the pH of the rinse water was at least over 6. In contrast, to achieve the benefits of improved conditioning, the microemulsion composition of the present invention does not have to be rinsed from the hair.
Cassidy, in U.S. Pat. No. 3,208,910, disclosed the use of a water-soluble zirconium carboxylate salt in a hair styling fluid to impart body, moisture resistance and sheen to human hair. Zirconium acetate, present in a concentration of 0.1 percent to 2 percent in a composition having a pH from about 3 to about 6, was used in a treatment for setting the hair. However, the treated hair behaved as if it were full of snarls and the hair was extremely difficult to comb when the concentration of zirconium acetate exceeded 2 percent. Consequently, body-enhancing and moisture-resistance effects could be imparted only by including auxiliary dispersing agents, like waxes and polymers; or by washing the hair with a soap-based shampoo to form an insoluble zirconium soap on the hair. However, in accordance with the present invention, the absolute concentration of the water-soluble metal salt is not limited and auxiliary agents, except for the water-insoluble amino-containing compound, are not required to produce the new and unexpected results of the present invention.
Similarly, Anzuino and Robbins, in the publication "Reactions of Metal Salts with Human Hair Containing Synthetic Polymers", J. Soc. Cosmet. Chem., 22, pp. 179-186 (1971), taught the polymerization of vinyl monomers, such as methacrylic acid or N,N-dimethylamino-ethyl methacrylate, within the keratin fibers of the hair to alter the chemical reactivity of the keratin. Then the polymer-containing hair fibers were reacted with metal salts, such as calcium chloride, nickel chloride, or zinc acetate, to improve the wet load extension properties of the hair. However, the method disclosed by Anzuino and Robbins involves a chemical reduction of the hair that imparts roughness, color lightening and other undesirable properties to the hair. In contrast, the composition and method of the present invention does not require a chemical reduction of the hair fiber and, rather than adversely affecting the hair, imparts improved and durable conditioning properties to the hair.
Homan, in U.S. Pat. No. 4,487,883, disclosed the use of a polymer having at least one nitrogen-hydrogen bond and an anhydrous additive, like a titanate, zirconate, or vanadate, in a hair-treating composition. According to the teachings of Homan, after application to the hair, the polymer is crosslinked upon exposure to moisture or humidity to provide hair conditioning and a hair set. A subsequent shampooing breaks the crosslinking bond, and the polymer, now in its original form, still acts as a conditioner, but does not maintain the hair set. However, the compositions disclosed by Homan suffer from the disadvantage of requiring storage in an anhydrous state. Such storage conditions usually are not practically feasible because it is difficult to insure that a commercial product remains moisture-free under normal production and storage conditions. Conversely, the microemulsion composition of the present invention is not limited to polymeric nitrogen-containing compounds, and the microemulsion composition has an aqueous base, thereby allowing normal production and storage conditions and a variety of formulation choices.
Similarly, European Patent Application No. 0117360 teaches the use of an aqueous composition including an emulsified polymer having at least one nitrogen-hydrogen bond and an organic zirconate, germanate and/or titanate, and having a pH of 6 to 8, in a process to condition and set the hair. The method and composition disclosed in European Patent Application 0117360 differs from the present invention in that the European disclosure operates well outside the pH range of the present invention and, more importantly, the composition utilizes nitrogen-containing polymers and organometallic compounds.
In U.S. Pat. No. 4,283,384, Jacquet et al. disclosed a composition including a particular type of polymer produced from an unsaturated monomer such as acrylic acid, a compound containing at least one hydroxyl functionality such as polyvinyl alcohol or pentaerythritol, and cerium ion. The polymer imparts good holding power to hair when the polymer is applied to the hair in a shampoo formulation. In the method of Jacquet, the cerium ion apparently is not involved in the interaction between hair and polymer. Furthermore, Jacquet et al. do not teach or suggest that the disclosed composition imparts a durable hair conditioning properties to the hair. In contrast, the present invention imparts conditioning properties to the hair, and exhibits unexpected conditioning durability, by efficiently depositing the conditioning agents on the hair.
In U.S. Pat. No. 4,614,200, Hsiung et al. disclosed utilizing an aqueous aluminum salt solution, without an amino-containing compound, to improve the set retention properties of hair at an ambient relative humidity of 50-60%. Hsiung et al. also taught that a polyvalent metal salt can be included in a standard hair conditioning formulation including a quaternary ammonium compound and a fatty amide compound to improve the conditioning properties of the hair. However, Hsiung et al. neither teach nor suggest using a metal salt in a clear microemulsion composition, further including an ester compound of structural formula EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2
and a water-insoluble amine or amino-functionalized silicone, to impart improved and durable conditioning properties to treated hair. As will be demonstrated more fully hereinafter, a fatty amide compound and a quaternary ammonium compound do not impart the improved esthetic and physical properties to hair that are imparted by a water-insoluble amino-containing compound, and a metal salt having a valence of at least II.
Abegg et al. in U.S. Pat. No. 3,958,581, disclosed a hair-treating composition including a divalent metal salt and a cationic polymer. Abegg et al. disclosed only the use of water-soluble cationic polymers having at least one tertiary amine or quaternary ammonium group in the polymeric chain and having a molecular weight of between about 1000 and 3,000,000. In contrast, the microemulsion composition and method of the present invention utilize water-insoluble monomeric primary, secondary and tertiary amines having a molecular weight substantially less than about 1000, or an amino-functionalized silicone polymer having only primary or secondary amino groups. Abegg et al. do not teach or suggest that a water-insoluble monomeric primary, secondary or tertiary amine having a molecular weight less than about 1000, or that an amino-functionalized silicone polymer including only primary or secondary amino groups, can be used with a divalent metal ion to impart improved physical or esthetic properties to the hair.
As also will be demonstrated more fully hereinafter, an important water-insoluble amino-containing compound useful in the composition and method of the present invention is an amino-functionalized silicone, like trimethylsilylamodimethicone. Silicone emulsions and microemulsions are well-known in the art of treating hair, but each known reference fails to teach or suggest that a stable microemulsion composition, suitable for treating hair, can be produced in a one-step process from a combination of a metal ion having a valence of at least II, a water-insoluble amino-containing compound, an ester compound of general structural formula EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2
and water.
For example Rosano, in U.S. Pat. No. 4,146,499, utilizes two surfactants in a four-step process of preparing an oil-in-water microemulsion. Rosano, in U.S. Pat. No. 4,472,291, also discloses the preparation of an oil-in-water microemulsion from a sole surfactant that has an electrostatic charge on the hydrophilic moiety of the surfactant. The viscosity of this microemulsion can be increased by adding a second surfactant to the microemulsion. In contrast, the method and composition of the present invention requires only a single, ester compound to form the microemulsion in a one-step process. Furthermore, and as will be demonstrated more fully hereinafter, a stable microemulsion composition of the present invention is formed regardless of the order of addition of the essential ingredients and is formed by employing a relatively low amount of the ester compound, such as from about 0.05% to about 15% by weight of the composition.
U.S. Pat. No. 4,388,437 to Ona discloses an emulsified composition including an amino-functionalized silicone and an organtitanate useful for treating fibers. The Ona composition does not include an ionizable metal salt or an ester compound having the general structural formula EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2.
In addition, Ona does not disclose that the composition is a microemulsion having a small droplet particle size or that the composition is useful to impart durable conditioning properties to hair.
Other patents disclosing emulsions including an amino-functionalized silicone include DeMarco et al. U.S. Pat. No. 4,529,586, wherein amodimethicone is emulsified with a cationic emulsifier to increase the effectiveness of a cationic hair conditioning compound. The present invention does not rely upon cationic polymer to impart conditioning properties to the hair. Chandra et al. in U.S. Pat. No. 4,559,227 discloses a solution or microemulsion of an amino-functionalized silicone achieved by using an anionic surfactant in conjunction with an alkanolamide or an amine oxide. Neither patent discloses the use of an ionizable metal salt nor the particular ester compounds utilized in the present invention as the sole emulsifier in a one-step process to provide a microemulsion composition useful for treating human hair.
In addition, Kohl et al. U.S. Pat. No. 4,749,732 discloses hair care uses of polydiorganosiloxanes containing aminoalkyl groups modified by alkoxycarbonylalkyl substituents. Kohl et al. modify the amino-functionalized silicone to reduce or eliminate incompatibility of the functionalized silicone with other composition ingredients. However, the stable microemulsion compositions of the present invention effectively isolate the functionalized silicone from other composition ingredients, like anionic surfactants, thereby precluding the need to modify the functionalized silicone. U.S. Pat. No. 4,563,347 to Starch discloses the use of amino-functionalized silicones in hair conditioning compositions to improve combing and feel characteristics. U.K. Patent Application Nos. 2,157,168 and 2,143,434 disclose the use of amino-functional silicones in hair care formulations such as a shampoo, a rinsed or a non-rinsed lotion, a restructuring composition, a composition for blow drying, and a composition for permanent waving. However, none of the references disclose or suggest the composition of the present invention or the use of an amino-functionalized silicone in a microemulsion composition.
Linn et al. in U.S. Pat. Nos. 4,797,272 and 4,797,273 disclose oil-in-water and water-in-oil microemulsions, including silicones and a relatively high amount of surfactants, such as from about 20% to about 80% by weight, suitable as moisturizers and sunscreens. However, Linn et al. do not suggest using a water-insoluble amino-containing compound, like an amino-functionalized silicone, in combination with a metal having a valence of at least II, in a composition to improve the conditioning properties of treated hair. Blehm et al. in U.S. Pat. No. 4,842,766 disclose microemulsions including amino-functionalized silicones and a cosurfactant having an HLB value of at least one. Blehm et al. require that the silicone-containing compound and the surfactant first be thoroughly admixed to form a clear composition prior to adding water to form the microemulsion. In contrast, the essential ingredients of the present composition can be added in any order to produce a stable, microemulsion composition.
U.S. Pat. No. 4,620,878 to Gee teaches a method of preparing a microemulsion composition from an oil concentrate including a silicon-containing compound having a polar radical, a surfactant that is insoluble in the silicon-containing compound and water. To form a microemulsion, the oil concentrate then is dispersed in a major amount of water. The present invention does not require the formation of an oil concentrate. In contrast, the microemulsion composition of the present invention can be produced directly from the individual essential ingredients.
U.S. Pat. No. 4,960,588 assigned to the same assignee as the present application, discloses a composition including a water-insoluble amino-containing compound, like an amine or an amino-functionalized silicone, and a metal salt useful for treating hair to impart durable hair set retention properties. However, the compositions disclosed in U.S. Pat. No. 4,960,588 were macroemulsions demonstrating varying degrees of stability. For example, large amounts of alcohol were incorporated into the macroemulsions to achieve a suitable degree of stability. In some instances, the amino-containing compound and the metal salt were applied to the hair from different vehicles in order to avoid the stability problems found on these macroemulsions. However, the present microemulsion compositions have overcome the stability problems of the macroemulsions of the prior art, and are useful in treating hair to impart improved and durable conditioning properties to treated hair.
Therefore, overall, not one of the above-discussed references either discloses or teaches a microemulsion composition suitable for treating human hair and comprising a water-insoluble amino-containing compound, like an amino-functionalized silicone or an amine; an ionizable metal salt, wherein the metal has a valence of at least II, like magnesium chloride or zinc chloride; an ester compound having the general structural formula: EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2,
wherein R.sub.1 is an alkyl group including from about eight to about 18 carbon atoms, R.sub.2 is an alkyl group including from one to about four carbon atoms, A is an alkylene oxide moiety wherein the alkylene group includes from one to about four carbon atoms and X is a number in the range of from about 4 to about 20; and water, and wherein the composition has a pH of less than 7, and preferably in the range of from about 3 to about 6.8, and a particle size in the range of from about 0.1 nm to about 250 nm, that, after application to human hair, imparts durable hair conditioning properties to the hair.
In contrast, to date, the compositions and methods used to treat and condition hair have suffered from sacrificing one beneficial hair conditioning property in order to achieve another beneficial hair conditioning property or from abnormally long times to treat the hair. Prior to the present invention, no known method or composition has been employed to effectively treat hair with a microemulsion composition within a few minutes to impart excellent and durable hair conditioning properties to hair.
Therefore, in accordance with the present invention, the physical and esthetic properties of hair are surprisingly and unexpectedly improved by contacting the hair with a microemulsion composition including a water-insoluble amino-containing compound, an ester compound having the general structural formula EQU R.sub.1 --O--(A).sub.X --CH.sub.2 CO.sub.2 R.sub.2,
and an ionizable metal salt, wherein the metal has a valence of at least II. The microemulsion composition can be applied to the hair from an aqueous or an aqueous/alcoholic vehicle, such as a hair spray, hair shampoo, or hair conditioner, at ambient temperature and is allowed to contact the hair for relatively short times to provide the benefits and advantages of improved physical and esthetic hair properties. Therefore, and as will be demonstrated more fully hereinafter, the method and composition of the present invention provide esthetically-pleasing, hair does not damage the hair and imparts excellent and durable conditioning properties, such as body and manageability, to the hair.